Research Outputs
Permanent URI for this communityhttps://hdl.handle.net/20.500.14288/2
Browse
4 results
Search Results
Publication Metadata only A reputation-based privacy management system for social networking sites(TÜBİTAK, 2013) Yüksel, Mehmet Erkan; Yüksel, Asım Sinan; Department of Computer Engineering; Faculty Member; Department of Computer Engineering; College of Engineering; 8693Social networking sites form a special type of virtual community where we share our personal information with people and develop new relationships on the Internet. These sites allow the users to share just about everything, including photos, videos, favorite music, and games, and record all user interactions and retain them for potential use in social data mining. This storing and sharing of large amounts of information causes privacy problems for the users of these websites. In order to prevent these problems, we have to provide strict privacy policies, data protection mechanisms, and trusted and built-in applications that help to protect user privacy by limiting the people who get access to a user's personal information. Thus, the privacy problem has prompted us to provide a solution that o ers the users of these social networking websites an opportunity to protect their information. In this paper, a social networking application and its system design, algorithm, and database structure are described. Our application o ers a reputation-based trusted architecture to social network users. It creates and monitors social reputations, nds social circles, and helps the users to group their friends easily, meaningfully, and automatically to protect their privacy. This system provides the grouping of users through an automated system into di erent social circles by analyzing the user's social connections depending on what common information or application they share that should not be accessed by other users.Publication Metadata only Access pattern-aware data placement for hybrid DRAM/NVM(TUBITAKScientific and Technical Research Council Turkey, 2017) Department of Computer Engineering; Erten, Didem Unat; Faculty Member; Department of Computer Engineering; College of Engineering; 219274in recent years, increased interest in data-centric applications has led to an increasing demand for large capacity memory systems. Nonvolatile memory (NVM) technologies enable new opportunities in terms of process-scaling and energy consumption, and have become an attractive memory technology that serves as a secondary memory at low cost. However, NVM has certain disadvantages for write references, due to its high dynamic energy consumption for writes and low bandwidth compared to DRaM writes. in this paper, we propose an access-aware placement of objects in the application code for two types of memories. Given the desired power savings and acceptable performance loss, our placement algorithm suggests candidate variables for NVM. We present an evaluation of the proposed technique on two applications and study the energy and performance consequences of different placements.Publication Open Access BlockSim-Net: a network-based blockchain simulator(TÜBİTAK, 2022) Ramachandran, Prashanthi; Agrawal, Nandini; Department of Computer Engineering; Biçer, Osman; Küpçü, Alptekin; Faculty Member; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; N/A; 168060Since its proposal by Eyal and Sirer (CACM '13), selfish mining attacks on proof-of-work blockchains have been studied extensively. The main body of this research aims at both studying the extent of its impact and defending against it. Yet, before any practical defense is deployed in a real world blockchain system, it needs to be tested for security and dependability. However, real blockchain systems are too complex to conduct any test on or benchmark the developed protocols. Instead, some simulation environments have been proposed recently, such as BlockSim (Maher et al., SIGMETRICS Perform. Eval. Rev. '19), which is a modular and easy-to-use blockchain simulator. However, BlockSim's structure is insufficient to capture the essence of a real blockchain network, as the simulation of an entire network happens over a single CPU. Such a lack of decentralization can cause network issues such as propagation delays being simulated in an unrealistic manner. In this work, we propose BlockSim-Net, a modular, efficient, high performance, distributed, network-based blockchain simulator that is parallelized to better reflect reality in a blockchain simulation environment.Publication Open Access Photonic integrated circuit-assisted optical time-domain reflectometer system(TÜBİTAK, 2022) Department of Electrical and Electronics Engineering; Onbaşlı, Mehmet Cengiz; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 258783Optical time-domain reflectometers (OTDR) are photonic systems that consist of an interrogator, a receiver and a fiber optical cable and have applications in telecommunications, security, environmental monitoring, distributed temperature and strain sensing. Since OTDR systems are bulk optical setups that consume multiple Watts of power, have large mass and volume footprint and are vulnerable to thermal drift, deployment of OTDR systems in the field is expensive, complicated and may not necessarily yield accurate sensing results. Thus, a compact, low-power, inexpensive and thermal drift-free OTDR system needs to be developed for improving the accuracy and the viability of OTDR in the field. In this study, I present the design and modeling of a photonic integrated OTDR system design based on IMEC's iSiPP50G silicon integrated photonic process design kit. The photonic integrated circuit includes a photonic modulator and a photodetector. Photonic power link budgets and the corresponding electronic signal-to-noise ratios are analyzed for 5-110 km fiber optical OTDR systems and power-efficient OTDR system designs are presented for inexpensive multiproject wafer fabrication.